Accession Number : ADD017981

Title :   System for Estimating Far-Field Acoustic Tonals.

Descriptive Note : Patent, Filed 30 Jun 94, patented 20 Feb 96,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Straus, James E ; Allman, Richard L ; Frisch, Willis L ; Nicholson, Matthew J ; White, Richard W

Report Date : 20 Feb 1996

Pagination or Media Count : 12

Abstract : A system and method for estimating a ship's far field acoustic characteristics includes at least one reference hydrophone and at least one movable hydrophone, both of which are disposed in the water closely adjacent the ship. The movable hydrophone senses acoustic tonals at a plurality of points on the surface of an imaginary prolate spheroid surrounding the ship, the major and minor axes of which are roughly equal to one half the length of the ship and the beam of the ship, respectively. The phase difference in the signals from the movable hydrophone and reference hydrophone are compared to generate a near field data set. A computer is used to estimate a far field data set representative of the ship's acoustic characteristics based on the near field data set. Thus actual far field measurements are not required.

Descriptors :   *SHIP NOISE, *MAPPING, *PATENTS, ACOUSTIC MEASUREMENT, HYDROPHONES, NEAR FIELD, AUDIO TONES, EXTRAPOLATION

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE